Conventionally, when manufacturing semiconductor components, flat panel displays, or the like, various kinds of processes such as cleaning, etching and plating are performed on a substrate such as a semiconductor wafer or a liquid crystal substrate by using a substrate processing apparatus.
As an example, a substrate processing apparatus that performs a plating process on a circuit pattern formed on a surface (a main surface, i.e., a surface on which the circuit pattern is formed) of a substrate includes a substrate rotating unit that rotates the substrate while holding the substrate horizontally; and a processing fluid discharging unit that discharges a processing fluid for plating (plating liquid) toward the surface of the substrate from a nozzle, which is movable along the surface of the substrate. Here, the plating liquid is set to be of a temperature higher than a surface temperature (room temperature) of the substrate. In this substrate processing apparatus, by discharging the plating liquid from the nozzle toward the surface of the substrate being rotated while moving the nozzle from a start position at a central portion of the substrate to an end position at an edge portion of the substrate, preset portions on the surface of the substrate are plated (see, for example, Patent Document 1).
Patent Document 1: Japanese Patent Laid-open Publication No. 2013-213263
Since, however, the processing fluid having the temperature different from the surface temperature of the substrate is used in the conventional substrate processing apparatus, a surface temperature at an outer region of the substrate becomes lower than a surface temperature at an inner region of the substrate if the processing fluid is discharged onto the surface of the substrate in a range from the start position at the central portion of the substrate toward the end position at the edge portion thereof. The reason why the temperature at the outer region of the substrate becomes lower may include heat dissipation from a peripheral end of the substrate or a difference in a rotational speed in a circumferential direction between the inner region and the outer region of the substrate being rotated (the rotational speed at the outer region is higher).
The performance of the plaiting liquid depends on the temperature of the plating liquid. Thus, if the surface temperature of the substrate is not uniform, it may be difficult to plate the preset portions on the surface of the substrate in a uniform manner, so that the substrate may not be processed effectively.